jueves, marzo 22, 2007

El primer dinosaurio excavador

El investigador David Varicchio de la Universidad Estatal de Montana (EE.UU.) y colabodores acaban de publicar en la revista inglesa Proceedings of the Royal Society la primera evidencia de un dinosaurio excavador. Se trata de los restos de un adulto y dos juveniles de un nuevo ornitópodo que han llamado Oryctodromeus cubicularis. Lo interesante del descubrimiento es que se encontraba en una enorme galería de un tamaño suficiente para que pudiera estar este dinosaurio. Según los investigadores esta relación es suficiente para interpretar que Oryctodromeus podía hacer galerias y vivir en ellas. La presencia del adulto y dos juveniles indica un comportamiento parental, de protección del adulto, tal y como hacen muchos mamíferos en la actualidad. La referencia es:

Varricchio, D. J., Martin, A. J. & Katsura, Y. 2007. First trace and body fossil evidence of a burrowing, denning dinosaur. Proceedings of the Royal Society,

Os adjuntamos el resumen a continuación

A fossil discovery in the mid-Cretaceous Blackleaf Formation of southwest Montana, USA, has yielded the first trace and body fossil evidence of burrowing behaviour in a dinosaur. Skeletal remains of an adult and two juveniles of Oryctodromeus cubicularis gen. et sp. nov., a new species of hypsilophodont-grade dinosaur, were found in the expanded distal chamber of a sediment-filled burrow. Correspondence between burrow and adult dimensions supports Oryctodromeus as the burrow maker. Additionally, Oryctodromeus exhibits features of the snout, shoulder girdle and pelvis consistent with digging habits while retaining cursorial hindlimb proportions. Association of adult and young within a terminal chamber provides definitive evidence of extensive parental care in the Dinosauria. As with modern vertebrate cursors that dig,burrowing in Oryctodromeus may have been an important adaptation for the rearing of young. Burrowing also represents a mechanism by which small dinosaurs may have exploited the extreme environments of polar latitudes, deserts and high mountain areas. The ability among dinosaurs to find or make shelter may contradict some scenarios of the Cretaceous–Paleogene impact event. Burrowing habits expand the known range of nonavian dinosaur behaviours and suggest that the cursorial ancestry of dinosaurs did not fully preclude the evolution of different functional regimes, such as fossoriality.

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